Poultry products make a significant part in the diets of Ukrainian citizens. Broiler chickens meat quality depends mainly on the quality and chemical composition of the feed the poultry consumes.

Mixed feed with the available nutrients provide a certain level of productivity, yield and nutritional value of poultry meat. Introducing a sufficient number of essential factors to animal feed enables to produce broiler meat containing no toxic compounds, hormones and antibiotics. Iodine is an essential nutrition factor and a required component of premixes and mixed feed for broiler chickens.

Iodine, through hormone action is involved in the regulation of oxidative processes, protein, carbohydrate, fat and mineral metabolism of the body. Lack of iodine in food is accompanied by thyroid gland hypofunction. Farm animals and poultry are very sensitive to lack of iodine in food.

Balancing rations for livestock and poultry is carried out using iodine premixes, which include the element in the form of iodine potassium compounds, potassium iodinewadding acid and sodium iodide.

Iodine, used in livestock feeding, is usually stabilized, so it can be  eliminated quickly.

We have developed the biotechnology of iodine enriched vermiculture biomass; we have also proved a positive impact of feed additives on broiler chickens performance.

The issue of the influence of the obtained iodide enriched food additive of vermiculture biomass on chemical composition, toxicity and biological value of broiler chickens remains unexplored.

Samples of thoracic and thigh muscles of cross Cobb-500 broiler chickens that consumed feed containing potassium iodide (control), chickens that received feed with 100% of iodine which was provided by red Californian worms hybrid biomass enriched with this element (1^st experimental group) and chickens that consumed feed containing 80.0% of the iodine norm due to the vermiculture biomass were selected for the research.

The chemical composition of meat was studied in terms of water content, dry matter, protein, fat, glycogen and ash. Determination of toxic compounds in broiler chickens meat and its biological value was performed using  three days old culture of Tetrashimena piriformis of WH14 strain.

While checking the chemical composition of broiler chickens muscle tissue we have found that under the influence of the iodide enriched vermiculture biomass significantly reduced water content in meat of the research chicken groups  and made 0.6% and 0.3% respectively.

A slight increase by 1.4% in dry matter content in muscle tissue of the 1^st experimental group was determined. In addition, unreliable increase by 1.97% in protein content in these samples of the product was found.

Fat content in muscle tissue of broiler chickens of the 2^nd experimental group  was at the same level as the control one. In the samples from experimental group poultry meat fat content was lower by 3.2% compared to the control indices.

A tendency of increase in glycogen mass fraction in poultry from the research groups was observed under the influence of iodine enriched vermiculture biomass. The difference compared to the control was 14.2% and 9.5% respectively.

Unreliable decrease in ash content compared to control was found out when analyzing the chemical composition of the research groups meat.

Thus, it was found that balancing feed for broiler chickens through adding iodine enriched vermiculture biomass does not cause deterioration of poultry meat chemical composition. On the contrary, it increases the nutrient content such as protein and glycogen, which in its turn, improves the nutritional value of meat as as humans nutrition.

One of the methods of establishing the biological value of broiler chickens meat is using Tetrashimena piriformis culture. This body test is very sensitive to chemical and biological agents that would identify biological value and toxicity of meat of broiler chickens quickly. This method application allows to make  preliminary assessment of the presence in chickens meat toxic agents of chemical and biological origin in 1-2 hours (within 24 hours). Biological value of the product can be determined within 72 hours under using Tetrashimena piriformis strain WH14.

Feeding broiler chickens with the fodder containing iodine enriched vermiculture biomass does not cause accumulation of the compounds that have toxic effects on Tetrashimena piriformis culture in the poultry muscle tissue.

Counting Tetrashimena piriformis cells showed that 1 cm³ of the medium containing chest and thigh muscles homogenate in the control group chickens is within 8,28 x 10⁴ and 8,85 x 10⁴ individuals.

It was found out experimentally that biological value of the pectoral and femoral muscles samples was higher compared with muscle tissue obtained from chickens in the control group under addition to feed broiler chickens iodine enriched vermiculture biomass (1^st and 2^nd research group).

Cultivating cells of Tetrashimena piriformis on the nutrient medium with homogenates of thigh and chest muscles isolated from the experimental group broiler carcasses allowed us to obtain 11.4% and 5.1% respectively,  larger amount of cells compared with the control samples.

Under adding homogenate of the second experimental group broiler chickens femoral and pectoral muscle the number of cells in 1 cm³ of medium was higher than in control samples by 2.0% and 4.4% respectively.

The research gives ground to say that the inclusion of iodine enriched vermiculture biomass into broiler feed does not cause accumulation of any biological or chemical toxic compounds in the chest and thigh muscles. In addition, iodine enriched vermiculture biomass additives increase the biological value of poultry meat as human food.

Key words: Iodine, broiler chickens, feed, iodine enriched vermiculture biomass, muscle tissue, meat chemical composition, Tetrashimena piriformis.